Quaternary climatic oscillations and geography are of primary importance in shaping intraspecific genetic diversity. We examined the diversification patterns and inferred processes for the green odorous frog (Odorrana margaretae) of western China. Species distribution modelling showed that the species has a continuous circular distribution around the Sichuan Basin while the basin itself is largely uninhabitable. Population genetic and phylogenetic analyses revealed that the species has a ring‐shaped divergent pattern. While the chain of populations around the Basin maintains a mostly gradual and continuous genetic variation, populations between the north and west showed little gene exchange. Two processes, glacial refugial history and geography, likely contributed to the observed patterns. Our genetic clustering analysis revealed two clusters, suggesting two refugial groups among the populations, one from the west and the other from the east. Postglacial expansion may have created two contact zones. One at the south had extensive population admixture and produced a gradual transition between the western and eastern populations. Consequently, this region has the highest genetic diversity and represents an evolutionary “melting pot.” In contrast, the second contact zone at the northwestern side of the Basin has limited admixture, suggesting partial reproductive isolation between the northern and western populations. Furthermore, an isolation‐by‐distance analysis revealed a strong correlation (Mantel r = 0.745) between the genetic and geographic distances, when we assumed that populations were connected following the circular distribution without gene flow across the NW contact zone. We also explored alternative explanations, such as a one‐refugium scenario. With its micro‐ring, the green odorous frog is poised to make an excellent model system for understanding the process of speciation.

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Islands species and their ecosystems play an important role in global biodiversity preservation, and many vulnerable island species are conservation priorities. Although insular habitat likely facilitates the species diversification process, it may also aggravate the fragility of these species with high risk of inbreeding. The Shedao pit-viper Gloydius shedaoensis is an island endemic species with an extremely high population density, which has been categorized as vulnerable in the IUCN Red List. We collected 13,148 SNP from across its genome and examined its genetic diversity and demographic history. The Shedao pit-viper has a low genetic diversity but shows no sign of inbreeding. Furthermore, population genetic structure analysis, including the NJ tree, PCoA, clustering, and spatial autocorrelation, revealed a general lack of spatial structure. Only the IBD residues suggested a weak patchiness. Overall, the population is nearly panmictic and gene flow is evenly distributed across the island. The large number of individuals, small size of the island, and the lack of population structure likely all contribute to the lack of inbreeding in this species. We also detected signs of male-biased dispersal, which likely is another inbreeding avoidance strategy. Historical demographic analysis suggested that the historical population size and distribution of the species are much larger than their current ones. The multiple transgressive-regressive events since the Late Pleistocene are likely the main cause of the population size changes. Taken together, our results provide a basic scientific foundation for the conservation of this interesting and important species.